How to find value in multidimensional object / array in Javascript?

Question

I have a multidimensional object (this is basically an array):

Object = { 1 : { name : bob , dinner : pizza }, 2 : { name : john , dinner : sushi }, 3 : { name : larry, dinner : hummus } } 

I want to be able to search for an object / array where the key is "dinner" and see if it matches with "sushi".

I know jQuery has $ .inArray, but it does not work on multidimensional arrays. Or maybe I'm wrong. indexOf also only works on one level of the array.

Is there a function or existing code for this?

Answer 1

If you have an array like

 var people = [ { "name": "bob", "dinner": "pizza" }, { "name": "john", "dinner": "sushi" }, { "name": "larry", "dinner": "hummus" } ]; 

You can use the filter method of an Array object:

 people.filter(function (person) { return person.dinner == "sushi" }); // => [{ "name": "john", "dinner": "sushi" }] 

In newer JavaScript implementations, you can use a function expression:

 people.filter(p => p.dinner == "sushi") // => [{ "name": "john", "dinner": "sushi" }] 

---

You can search for people with "dinner": "sushi" using map

 people.map(function (person) { if (person.dinner == "sushi") { return person } else { return null } }); // => [null, { "name": "john", "dinner": "sushi" }, null] 

or reduce

 people.reduce(function (sushiPeople, person) { if (person.dinner == "sushi") { return sushiPeople.concat(person); } else { return sushiPeople } }, []); // => [{ "name": "john", "dinner": "sushi" }] 

I am sure you can generalize this to arbitrary keys and values!

Answer 2

jQuery has a built-in jQuery.grep method that works similar to the ES5 filter function from @adamse Answer and should work fine in older browsers.

Using the adamse example:

 var peoples = [ { "name": "bob", "dinner": "pizza" }, { "name": "john", "dinner": "sushi" }, { "name": "larry", "dinner": "hummus" } ]; 

you can do the following

 jQuery.grep(peoples, function (person) { return person.dinner == "sushi" }); // => [{ "name": "john", "dinner": "sushi" }] 

Answer 3

If you intend to frequently perform this search, consider changing the format of your property, so dinner is actually the key. This is similar to assigning a primary cluster key in a database table. So for example:

 Obj = { 'pizza' : { 'name' : 'bob' }, 'sushi' : { 'name' : 'john' } } 

Now you can easily access it as follows: Object['sushi']['name']

Or, if the object is really so simple (just the "name" in the object), you can simply change it to:

 Obj = { 'pizza' : 'bob', 'sushi' : 'john' } 

And then enter it like this: Object['sushi'] .

Obviously, this is not always possible or in your interests to restructure your data object like this, but the fact is that it is best to answer the question whether your data object is structured in the best way. Creating such a key can be faster and create cleaner code.

Answer 4

 var getKeyByDinner = function(obj, dinner) { var returnKey = -1; $.each(obj, function(key, info) { if (info.dinner == dinner) { returnKey = key; return false; }; }); return returnKey; } 

jsFiddle .

So far, -1 never a valid key.

Answer 5

You can find the object in the array using Alasql :

 var data = [ { name : "bob" , dinner : "pizza" }, { name : "john" , dinner : "sushi" }, { name : "larry", dinner : "hummus" } ]; var res = alasql('SELECT * FROM ? WHERE dinner="sushi"',[data]); 

Try this example in jsFiddle .

Answer 6

You can use a simple for loop:

 for (prop in Obj){ if (Obj[prop]['dinner'] === 'sushi'){ // Do stuff with found object. Eg put it into an array: arrFoo.push(Obj[prop]); } } 

The following script example puts all objects containing dinner:sushi into an array:

https://jsfiddle.net/3asvkLn6/1/

Answer 7

There are already a lot of good answers here, so why not, use a library like lodash or underscore :)

 obj = { 1 : { name : 'bob' , dinner : 'pizza' }, 2 : { name : 'john' , dinner : 'sushi' }, 3 : { name : 'larry', dinner : 'hummus' } } _.where(obj, {dinner: 'pizza'}) >> [{"name":"bob","dinner":"pizza"}]